Fan Clutch Diagnostics

[garyp285]

I have the 03 FSM and cannot find the procedure to check the pins on the fan plug, except for using a DRBlll.
I'm seriously considering the 7.3 powerstroke clutch conversion.
Thanks for any advice

 

[BigPapa]

This what you need?

 

[garyp285]

Awesome, thanks very much, I'll check it out.

 

[BigPapa]

This is the other test for Fan Speed:

 

[sag2]

Remember those diagnosis trees only work if you have an active code. If you have no codes or it is stored and not active, it will always lead you to the module as the cause. Biggest mistake made by technicians, hence all the modules that get replaced that are not bad.

 

[BigPapa]

Good point.

 

[garyp285]

Sorry, Is driver 1, and return 6

 

[garyp285]

The only reading I get is between 1 and 6, and is 7.5 ohms.
Jumping 1 to any others shows 1 ohm.
BTW with engine cold the fan will not rotate 1/4 turn when spinning by hand, but when hot is has very little resistance.

 

[Bob4x4]

You can not fully diag without a scanner that can see commanded,actual and sometimes the rpm can help.It is pretty expensive to be guessing.Changing to any other fan clutch will result in dtc's and to fail smog test

 

[garyp285]

Thanks Bob4x4, Its frustrating since I just got back from Gulf Shores, after breaking down 100 miles from home, and had to have the truck and 5th wheel towed to a dealer in Tupelo Ms that cost $900 for a water pump, and crank sensor, and then ran HOT again near home.
It looks like the coolant level dropped a little, so now I'm thinking maybe a head gasket.

 

[garyp285]

I'm waiting on a fan clutch, and bearing from Genos, and if that doesn't cure hot ac at idle I'll be adding an electric fan with temp probe in the condenser.

 

[Wayne M.]

Gary, can you start over from square one? Why you're after the clutch?
When I did my water pump, my tank dropped once. Air purge.

 

[sag2]

I'm waiting on a fan clutch, and bearing from Genos, and if that doesn't cure hot ac at idle I'll be adding an electric fan with temp probe in the condenser.

Is hot air blowing out of the A/C at idle the problem your trying to fix? There was a flash on the early trucks that made sure the fan came on when the engine was cold so the A/C system did not blow the high pressure relief.

 

[garyp285]

When I had it charged it May it ramped up at idle, but its been acting up since June, and I never hear the roar anymore. The truck by itself will run about 200 to 220, but when I'm towing the 10k 5th wheel it starts climbing unless I stay at 60mph.
I checked it for soft codes and getting P0480, and I bet the dealer did not even look when they replaced the water pump.
I also put a glove on and cranked it cold, turned on ac, and then stopped and held the fan with no resistance hardly at all, then checked the pins on the fan harness and got nothing except between 1 and 6, 7.5ohms.

Sag, Trying to fix the overheating, and ac condenser getting to hot, which the new fan clutch will hopefully do.

 

[Wayne M.]

I'm waiting on a fan clutch, and bearing from Genos, and if that doesn't cure hot ac at idle I'll be adding an electric fan with temp probe in the condenser.

I think you're on the right track. Mine didnt get quite hot, but when I changed the clutch, my AC came back and so did the roar at lo engine speed.

 

[DaveHess]

Gary, I'm no master mechanic by any stretch of the imagination, but I noticed you stated the engine gets hot unless you keep the speed to 60 MPH. I am having the same issue with mine while towing but not to your extreme. I only bring this up as a possibility as I don't see anyone else has broached the topic but mine will heat up to about 208 while towing at speeds over 65 and in ambient temperatures over 80 degrees. For the record, I tow at 67 because that puts the RPM at 1900. If I bring my speed down to 55 or 60, the coolant temperature will slowly return to 193 to 198 every time. While on vacation this summer, my brother (diesel mechanic) and I probed this problem and determined I have an airflow issue. It is very difficult to see physically between the coolers (4) but we're pretty sure after 14 years of towing and driving, the radiator has a bunch of stuff plastered over the front of it restricting airflow through the radiator. Not totally blocking it but at least restricting it. This is sort of confirmed by my slowing the truck down and slowing the RPM down and the coolant flow through the radiator . The coolant spends more time in the radiator and the coolant temperature comes down. I was thinking maybe you have two problems going on at the same time (Fan speed and airflow). Just a thought.

 

[garyp285]

Dave, you might be right, and would not be a bad idea to check this out.
thanks, Gary

 

[DaveHess]

Gary, As soon as the weather stays cool here, I am going to get the A/C evacuated and then take each of the coolers off to clean the radiator. We could see "fuzzy" stuff all over the front of the radiator.

 

[garyp285]

Just finished up installing new fan clutch, and all I can say is it's awesome. It moves so much air the condenser barely gets warm before the computer ramps up the fan, and when I turn the ac off the fan slows down after cooling off the condenser. There won't be any problem having ac while idling now, and I'm going to stop looking at new trucks for a while.

I had thought about adding an electric fan to help the ac, but that will not be needed now. I just hope I didn't hurt anything running it hot a few times, and when the WP went out.
Thanks for all the great advice from everyone.
Gary

 

[Wayne M.]

Good to hear. Have a great weekend!